Investors Bought Into Nearly $250 Billion in Global I.P.O.s in 2014

After months of hype and breathless anticipation, the Alibaba Group — China’s answer to eBay and Amazon — raised $25 billionin its market debut in September, setting a record for initial public offerings.

Not three months later, the car-ride start-up Uber raised an eye-popping $1.8 billion, one of the biggest fund-raising rounds in venture capital history.

In other words, it was a very good year for the business of raising money — in either the public or the private markets. Still, investors and advisers are beginning to question whether that performance can be repeated this year.